Evaporator having means for removing tubes therefrom



June 19, 1951 J. w. LITTLE 2,557,356

EVAPORATOR HAVING MEANS FOR REMOVING TUBES THEREFROM Filed March 11, 1948 2 Sheets-Sheet l INVENTOR. John W Ll-H/n June 19, 1951 J. w. LITTLE 2,557,356

EVAPORATOR HAVING MEANS FOR REMOVING TUBES THEREFROM Filed March 11, 1948 2 Sheets-Sheet 2 a INVENTOR.

John W L1?"7"/ firmemsys Patented June 19, 1951 EVAPORATOR HAVING MEANS FOR REMOV- ING TUBES THEREFROM John W. Little, Birmingham, Ala., assignor to Goslin-Birmingham Manufacturing Company, Inc., a corporation of Alabama Application March 11, 1948, Serial N0. 14,188

3 Claims. (01. 257224) My present invention relates to an apparatus for removing worn or damaged tubes from an evaporator or the like preparatory to replacing the same with new tubes.

In the art to which my invention relates,-the prior method of retubing an evaporator or similar piece of apparatus consisted in loosening the upper end of the tubes from the upper tube sheet and driving the tubes downwardly, one at a time, through the lower tube sheet. The holes in the tube sheet for receiving the tubes are only slightly larger in diameter than the tubes themselves, in most apparatus being about e inch larger in diameter. After such apparatus has been in use for a length of time sufficient toi require replacement of the tubes, it is found that each tube is encrusted on the outside with hard deposits of scale. The thickness and character of such encrustation is such as to considerably increase the diameter of the tube. In driving the tubes downwardly to remove the same as heretofore practiced, substantially the entire coating of scale had to be sheared off during the passage of the tube through its opening in the tube sheet. This operation is extremely laborious, expensive and time consuming, and sometimes results in major damage to the tube sheet.

It is the principal object of my invention, therefore, to overcome the above difliculties by providing one or more auxiliary openings in the lower tube sheet of a diameter to fully pass an encrusted tube, normally closed by a suitable removable cover, through which the tubes are passed after being cut adjacent the bottom end, and freed at the upper end from the upper tube sheet, thereby making it unnecessary to drive the encrusted tubes through the tube receiving openings of the lower tube sheet.

Another object of my invention is to provide a removable cover and holddown therefor especially adapted to form the closure for the tube openings in the tube sheet, and which shall be simple of construction and easily removed when it is desired to retube the evaporator.

Apparatus illustrating the features of my invention is shown in the accompanying drawings forming a part of this application in which:

Fig. 1 is an elevational view of one type of evaporator with which my improved tube removing means may be associated;

Fig. 2 is a somewhat diagrammatic verticalsectional view through the apparatus shown in Fig. i, and illustrating a tube in the process of being removed through the lower tube sheet, the covers for the vapor head and the bottom being re moved;

Fig. 3 is an enlarged sectional view taken along 2 the line III--III of Fig. 2, only a few of the tubes being shown;

Fig. 4 is a sectional view drawn to an enlarged scale and illustrating the cover for one of the auxiliary openings in the lower tube sheet; and,

Fig. 5 is a sectional view taken along line VV of Fig. 4.

Referring now to the drawings for a better understanding of my invention, I illustrate the same in association with a well known type of vertical tube evaporator having a body I0, and upper and lower tube sheets I I and I2. The body is provided with man holes l3 and covers I4 therefor through which a workman may enter the evaporator above the lower tube sheet I2. The evaporator may be supported with the lower tube sheet elevated a considerable distance above the floor line, the specific type of base I5 being shown, described, and claimed in an application filed in the names of John W. Little and Joseph H. Kelly on March 29, 1948, Serial No. 17,666. The base i5 is provided with a plurality of walkin openings I6 whereby a workman may enter beneath the lower end of the evaporator. The bottom cover I? for closing the lower end of the evaporator is shown in lowered position Within the base I5.

As understood, the evaporator also comprises a tube nest I8 embodying a multiplicity of individual tubes T disposed between the upper and lower tube sheets. The tubes are expanded into the openings of the upper tube sheet I I and similarly expanded into the openings of the lower tube sheet I2. The tubes are thus made fluid tight with respect to the tube sheets, and steam is admitted through a suitable conduit I9.

Directly in front of each of the man holes I3 I provide in the periphery of the lower tube sheet I2 an opening 2 I. These openings preferably are of a size to freely pass an encrusted tube, and in normal operation of the evaporator are closed by means of a cover 22. As best shown in Figs. 4 and 5, the covers 22 carry an integrally formed depending portion 23. The depending portion 23 is provided with an elongated slot 24, having its bottom notched out as indicated at 26. A bolt 2'! is slidably received in the notch 26, the head 28 thereof engaging the shoulders at the bottom of the opening 2 The threaded end of the bolt 21 passes through a yoke 29 disposed to contact the lower surface of the tube sheet I2 and is held in place thereagainst by means of a nut 3| and washer 32. A gasket 33 is interposed between the cover 22 and the tube sheet I 2 whereby when the nut is tightened about the bolt 21 the opening 2| is effectively sealed.

I 1 From the foregoing the method of retubing an permit the covers 22 to be pushed upwardly from the bottom Where they may be removed through the manholes I3. An operator, working through the manholes 3 with a suitable tool, cuts the tubes closest the openings 2 I. A workman at the top of the body, above the upper tube sheet II and using a suitable tool, loosens the upper ends of the tubes from the upper tube sheet. As soon as a tube is loosened from the upper tube sheet I I, the workman at manhole I3 pulls the free end of the tube over and down into the opening 21 as shown diagrammatically in Fig. 2 of the drawing. The tube falls by gravit until its lower end strikes the floor on which the evaporator rests, whereupon a workman cuts a section from the end of the tube, projecting beneath the lower tube sheet. The section thus cut is discarded through the opening it and this operation is repeated until the entire tube is cut up into short lengths and removed from the evaporator. This process is continued until all of the tubes areremoved, it being understood that the stub ends 36 left in the lower tube sheet are removed by drawing the same upwardly or downwardly. The new tubes may now be placed in the evaporator from the top thereof through the vapor head opening and secured both to the upper and lower tube sheets.

As stated, the openings 2| are of a diameter 'to pass an encrusted tube without the necessity of forcing the same therethrough. While the diameter of the openings 2! will vary for different apparatus, I have found that for an evaporator having 2 inch diameter tubes, openings of 3% inches in diameter are quite satisfactory.

Likewise, while I show and describe an opening 2i disposed directly inward from each manhole 53, it will be apparent that only one such opening would suiiice since the lower ends of the tubes may be moved about when the upper ends thereof are freed from the upper tube sheet.

From the foregoing it will be apparent that I have devised an improved arrangement adapted for association with an evaporator or the like by means of which the tubes thereof may be readily and easily removed. It is apparent that the method of cutting the tubes adjacent the lower ends thereof, passing them through the lower tube sheet, and cutting the same into short lengths provides a simple and effective way of removing the tubes without shearing the layer of scale along the entire length thereof as has heretofore been the practice.

The particular style of cover shown in Figs. and 5 of the drawings and the hold down means therefor make it possible to place the cover on the top of the lower tube sheet l2 whereby the pressure within the evaporator aids in sealing the opening 2!. It will be apparent that an evaporator embodying my improved tube removing means may be quickly retubed, thus to put the same back into operation within a minimum of time.

While I have shown and described my improved arrangement in association with a vertically disposed evaporator, it may be employed with evaporators of other types. Likewise, while I have stated that the openings 2| are provided in the lower tube sheet, in some types of evaporators ,it will be found expedient and more practical to provide them in the upper tube sheet, and in some horizontal evaporators, in either of the tube sheets. In some units such as horizontal tube condensers or in vertical evaporators, boilers, or condensers it is not necessary to cut the tubes into short lengths after they are passed through the tube sheet, since some such units are so disposed as to provide space for withdrawing the entire length of the tube.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications, without departing from the spirit thereof, and I desire, therefore, that onl such limitations shall be placed thereupon as are specifically set forth in the appended claims.

What I claim is:

1. In an evaporator embodying a body having spaced tube sheets therein and a plurality of tubes connected directly at their ends to the tube sheets, the combination of a man hole providing adjacent the manhole, and a removable closure for said opening.

2. In an evaporator embodying a body having upper and lower tube sheets with a plurality of tubes connected directly at each end to the tube sheets, a manhole providing an entrance way into a s' e of the body below the upper tube sheet and immediately adjacent the lower tube sheet, an opening in the lower tube sheet of a size to freely pass an encrusted tube and disposed at the periphery of the lower tube sheet adjacent the manhole, said opening, being normaiiy unoccupied by a tube, and a removable cover for said opening accessible for removal through said manhole.

3. In an evaporator embodying a body with spaced tube sheets therein and a plurality of Number tubes connected at the ends directly to the tube sheets, the combination of an opening adjacent the periphery in one of the tube sheets of a size to freely pass an encrusted tube and normally unoccupied by a tube, a removable closure said opening, and means giving access to the interior of the evaporator adjacent said opening for removal of a tube therefrom.

: JOHN W. LITTLE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

